Epidemiological studies show associations between chronic noise exposure and disease, but the biological pathways remain poorly understood. In this explorative pilot study, we investigate the mechanisms that may link sleep disruption by environmental noise with disease, and the efficacy of a non-pharmacological intervention to mitigate these effects. We conducted a cross-over trial (ClinicalTrials.gov: NCT05319262; 2022-03-09) where N = 12 healthy individuals slept for five consecutive nights in acoustically isolated bedrooms. Nights included one familiarisation night; one quiet baseline night; one night with road, rail and air traffic noise of levels 45-65 dB LAS,max; one night with continuous 45 dB broadband pink noise; and one night with both traffic noise and pink noise. Sleep was measured with polysomnography. Perceived sleep quality and recouperation were measured with morning questionnaires. Daily blood samples were collected for metabolomics analysis. Here we show that discrete traffic noise events induced acute elevations of the odds ratio product, indicating acute sleep fragmentation, even while total sleep time and overall sleep macrostructure were preserved. Traffic noise is further associated with significant elevations in concentrations of leucine, lactic acid, and acetone relative to quiet control. Sleep and metabolic disturbances by traffic noise are attenuated when pink noise is played continuously throughout the night. Noise-induced sleep fragmentation is followed by changes in metabolic processes that in the long-term may be precursors for cardiometabolic disorders. Masking of traffic noise by continuous, neutral sound may mitigate acute physiological sleep disturbance and downstream metabolic effects. These results should be interpreted cautiously, given the limited sample size and subject homogeneity. This study explored how environmental noise at night might affect health and whether a simple sound-based intervention could help. Twelve healthy adults slept under different sound conditions, including quiet, traffic noise, and continuous low volume noise, termed “pink noise”. Researchers measured sleep quality and changes in certain compounds in the blood. Traffic noise caused brief disruptions in sleep and altered levels of certain compounds linked to energy use. However, during continuous playback of pink noise, these negative effects were reduced. These findings suggest that even when total sleep time is not affected, noise can disturb the body’s physiology in ways that may affect long-term health. Continuous neutral sounds like pink noise could help protect sleep and well-being in noisy environments. Vincens et al. investigate how traffic noise and masking pink noise impact physiological sleep, cognition, and metabolic blood biomarkers. Traffic noise acutely fragments sleep even while total sleep time is preserved, and is followed by metabolic disturbances, the effects of which are attenuated by continuous pink noise.

OBJECTIVE:This study investigated the potential impact of sound exposure in preschools on children's hearing function by measuring distortion product otoacoustic emissions (DPOAE) over time. DESIGN:A longitudinal repeated-measures approach was employed to evaluate how DPOAE amplitudes varied with sound exposure and pre-school attendance duration, analysed using general estimation equation (GEE) modelling. STUDY SAMPLE:The sample included 62 children aged three to six years attending preschools. Sound exposure levels and DPOAE amplitudes were measured during time being indoor. RESULTS:Average indoor sound levels (time indoors (Ti)) were 81 dB LAeqTi, with highest noise events reaching 112 dB LAFmax. A total of 31 measurements (52%) exceeded 80 dB LAeqTi. GEE analysis showed a significant decrease in DPOAE amplitudes at 6 and 8 kHz in the right ear in relation to sound exposure levels, suggesting a sound level-dependent effect. Time spent in pre-school revealed a decrease in DPOAE amplitudes at 3 and 4 kHz in the right ear over the day and week, indicating cumulative effects of sound exposure. CONCLUSIONS:The findings suggest that pre-school sound exposure may adversely affect children's hearing, particularly at higher frequencies and over time. Further research is needed to validate these results and explore long-term implications of early-age noise exposure.

OBJECTIVES:The objectives of this study were to examine if Swedish female preschool teachers had a higher relative risk of experiencing symptoms of a voice disorder than women from the general population and if preschool teachers who experienced noise in the working environment had a higher risk of voice disorders than preschool teachers who did not experience noise at work. METHOD:Questionnaire data from 4718 female preschool teachers with teacher degrees issued from universities in Västra Götaland County in Sweden and 4122 female controls were analyzed using three outcome questions: a) hoarseness without having a cold, b) tiredness in voice and throat when talking a lot, and c) tiredness in voice and throat when reading aloud or giving an oral presentation. Prevalence of symptoms of a voice disorder and confounder adjusted risk ratio (RR) with 95% confidence intervals was assessed in preschool teachers compared to controls using log-binomial regression. A sub-analysis was performed among the preschool teachers currently working in preschool, estimating the risk of symptoms of a voice disorder in relation to two questions on noise at work, asking how often they are exposed to such high sound levels that they have to 1) raise their voice to be able to talk to others and 2) have difficulty hearing what people are saying. RESULTS:Compared to controls, the preschool teachers had a higher prevalence and significantly higher RRs for all symptoms of a voice disorder. For tiredness in voice and throat when reading aloud or giving an oral presentation, the risk was increased more than threefold for teachers compared to controls (RR: 3.7; 95% confidence interval, CI: 3.2-4.3), and the risk was increased by more than twofold for the outcomes hoarseness without having a cold (RR: 2.1; 95% CI: 1.7-2.5) and tiredness in voice and throat when talking a lot (RR: 2.5; 95% CI: 2.3-2.8). In addition, among preschool teachers, a dose-response relationship was found for all voice outcomes in relation to noise exposure at work, such that increasingly higher ratios were found among those reporting more noise exposure. CONCLUSION:Swedish female preschool teachers have a higher risk of experiencing symptoms of a voice disorder than women who have never worked in preschool. Furthermore, being exposed to high sound levels in the preschool working environment is associated with increasingly high risks of symptoms of a voice disorder. These results indicate a need for voice ergonomic interventions to improve the preschool teachers working environment.

BACKGROUND:Preschool children are regularly exposed to high noise levels that may affect hearing. A previous study has linked preschool noise exposure to reduced distortion product otoacoustic emission (DPOAE) amplitudes. Since DPOAEs primarily reflect outer hair cell (OHC) activity, they provide an indirect marker of cochlear function. Measurement accuracy can be affected by middle-ear pressure. Pressurised DPOAEs (pDPOAEs) compensate for middle-ear pressure during recording. METHODS:This cross-sectional study aimed to examine the relationship between preschool noise exposure and pDPOAE amplitudes while accounting for middle-ear pressure. Seventy-five children (4-6 years old) were monitored using dosimeters to measure the equivalent continuous sound level (LAeqTi) and the 95th percentile of maximum levels (LAFmax,95). Of these, 56 children completed pDPOAE testing at four time points during the preschool week. Linear mixed-effects models evaluated associations with noise exposure, time of day and progression across the week. RESULTS:For personal dosimetry, the mean LAeqTi was 80 dB (range: 60-98 dB) and the mean LAFmax,95 was 97 dB (range: 77-110 dB). Most LAeqTi levels (86.2%) were between 75-85 dB, with LAFmax levels exceeding 115 dB in 53.8% of the cases. No significant associations were found between LAeqTi or LAFmax,95 and pDPOAE amplitudes (p > 0.05). Time-of-day differences were observed, with higher amplitudes in the afternoon at 4 kHz (p = 0.045) and 6 kHz (p = 0.047) in the right ear, and 3 kHz in the left ear (p = 0.021). Girls showed higher amplitudes than boys at 4 kHz in the left ear (p = 0.030). CONCLUSIONS:Although pDPOAE amplitudes varied with time of day, and sex, a direct exposure-response relationship with preschool noise was not demonstrated. Short-term variations in typical preschool noise exposure may not measurably affect cochlear function in young children. Future research should refine exposure assessment and recording protocols to reduce variability and improve detection of small physiological changes.

A participatory-based intervention was performed in Sweden, aimed at improving the sound environment in one preschool (n = 20) and one obstetric ward (n = 50), with two controls each (n = 28, n = 66). Measured sound levels, and surveys of noise annoyance, hearing-related symptoms and emotional exhaustion were collected before, and three and nine months after the interventions, comparing intervention and control groups over time. The results of this first implementation in a limited number of workplaces showed significantly worsening of hyperacusis, sound-induced auditory fatigue, emotional exhaustion and increased sound levels in the preschool, and worsening of noise annoyance in both intervention groups. Increased risk awareness, limited implementation support and lack of psychosocial interventions may explain the worsening in outcomes, as might the worse baseline in the intervention groups. The complexity of the demands in human-service workplaces calls for further intervention studies.

OBJECTIVE:The aim of the study was to explore and describe how workers in communication-intense workplaces in health care and preschools experience the sound environment. The dependence on vocal communication and social interaction poses a challenge using hearing protection in these working environments.METHOD:A qualitative method was used, more specifically inductive thematic analysis was used, as this approach was deemed suitable to explore the staff's experiences of the sound environment. Data were collected by interviews and to increase trustworthiness, several researchers were involved in the data collection and analysis.STUDY SAMPLE:Workers from two preschools, one obstetrics ward and one intensive care unit took part in the study.RESULTS:Four main themes emerged from the thematic analysis: A challenging and harmful sound environment; Health-related effects of a challenging and harmful sound environment; A good sound environment is not prioritised; and Resourceful and motivated staff.CONCLUSIONS:Workers in communication-intense workplaces in preschools, obstetrics care and intensive care reported that there was a relationship between the sound environment and negative health effects. In addition, the results suggests that the high motivation for change among staff should be utilised together with an increased prioritization from the management to reach innovative context specific improvements to the sound environment in communication intense working environments.

BACKGROUND: Noise is a common workplace problem that can affect health and performance. High sound levels have been found in sectors that largely has been overlooked in noise research such as health care and education. In these communication-intense environments the work requires speech communication, thus making it difficult to wear hearing protection. OBJECTIVE: To explore nurses’ and preschool teachers’ experiences of taking part in a participatory intervention project aiming to improve the sound environment and the psychosocial work environment. METHODS: One preschool and one obstetrics ward took part in the study, and a qualitative design was used to evaluate the experience of the participatory intervention approach. RESULTS: Five main themes were found in the analysis: Awareness; Taking control of the sound environment; Influence of the building and interior design; Circumstances influencing the intervention process; and Motivation to maintain change. CONCLUSIONS: Despite demanding working situations and lack of financial resources, preschool and obstetrics staff described being creative in planning and implementing several different solutions to improve the sound environment at their workplaces, while interventions specifically improving the psychosocial work environment were fewer. Hence, our study suggest that a participatory intervention approach may facilitate participation and motivation, but resources and support are needed for a comprehensive and effective implementation.

The aim was to assess the risk of hyperacusis in relation to occupational noise exposure among female workers in general, and among women working in preschool specifically.A retrospective longitudinal study was performed. Survey data were collected in 2013 and 2014 from two cohorts: randomly selected women from the population in region Västra Götaland, Sweden, and women selected based on having received a preschool teacher degree from universities in the same region. The final study sample included n = 8328 women born between 1948 and 1989. Occupational noise exposure was objectively assigned to all time periods from the first to the last reported occupation throughout working life, using the Swedish Job-Exposure Matrix (JEM) with three exposure intervals: <75 dB(A), 75 to 85 dB(A), and >85 dB(A). The JEM assigns preschool teachers to the 75 to 85 dB(A) exposure interval. The outcome hyperacusis was assessed by self-report using one question addressing discomfort or pain from everyday sounds. In the main analysis, a hyperacusis event was defined by the reported year of onset, if reported to occur at least a few times each week. Additional sensitivity analyses were performed using more strict definitions: (a) at least several times each week and (b) every day. The risk (hazard ratio, HR) of hyperacusis was analyzed in relation to years of occupational noise exposure, using survival analysis with frailty regression modeling accounting for individual variation in survival times which reflect, for example, noise exposure during years prior to onset. Occupational noise exposure was defined by the occupation held at year of hyperacusis onset, or the occupation held at the survey year if no event occurred. Models were adjusted for confounders including age, education, income, family history of hearing loss, and change of jobs due to noise.In total, n = 1966 hyperacusis events between 1960 and 2014 were analyzed in the main analysis. A significantly increased risk of hyperacusis was found among women working in any occupation assigned to the 75 to 85 dB(A) noise exposure group [HR: 2.6, 95% confidence interval (CI): 2.4-2.9], compared with the reference group <75 dB(A). The risk was tripled among preschool teachers specifically (HR: 3.4, 95% CI: 3.0-3.7), with the crude Kaplan-Meier curve showing a higher rate of onset early in the working life in preschool teachers compared with all the other exposure groups. The risk was increased, but not statistically significant in the main analysis, for the highest exposure group >85 dB(A), where only six hyperacusis events were identified (HR: 1.4, 95% CI: 0.6-3.1). In the sensitivity analysis, where hyperacusis was defined as occurring every day, the HR was significant also in the highest exposure group (HR: 3.8, 95% CI: 1.4-10.3), and generally slightly higher in the other exposure groups compared to the main analysis.This study indicates increased risk of hyperacusis already below the permissible occupational noise exposure limit in Sweden (85 dB LAeq,8h) among female workers in general, and in particular among preschool teachers. Prospective studies and less wide exposure intervals could confirm causal effects and assess dose-response relationships, respectively, although this study at present suggest a need for risk assessment, improved hearing prevention measures, and noise abatement measures in occupations with noise levels from 75 dB(A). The results could also have implications for management of occupational disability claims.

To examine the effect of work-related stress and road noise exposure on self-rated sleep and potential additive interaction effects. Sleep and predictor variables were surveyed within two subsamples with 2191 and 1764 working women in a cross-sectional study. Sleep was assessed using a single question on general sleep quality and four questions on specific sleep problems and subsequently dichotomized (poor sleep vs. no poor sleep). Work-related stress was operationalized by job strain and effort-reward imbalance. Nocturnal exposure to road traffic noise was assessed as (a) the orientation of the bedroom window to a quiet façade vs. a low-, medium- or high-trafficked street and (b) energy-equivalent sound pressure levels for night-time modelled at the most exposed façade (Lnight). We distinguished between low (< 45 dB(A)), medium (45–50 dB(A)) and high exposure (> 50 dB(A)). Poor sleep was associated with job strain and effort-reward imbalance. The prevalence of poor sleep did not increase with increasing Lnight, but bedroom window orientation showed a non-significant trend. A quiet façade had a protective effect on sleep in each Lnight category. We found a non-significant trend for an additive interaction between bedroom window orientation and job strain. Noise levels modelled for the most exposed façade likely overestimate the actual exposure and thus may not be a precise predictor of poor sleep. Bedroom window orientation seems more relevant. Potential additive interaction effects between bedroom window orientation and job strain should be considered when interpreting epidemiological study results on noise-induced sleep disturbances.

PURPOSE:To assess whether working in preschools increases the risk of hearing-related symptoms and whether age, occupational noise, and stressful working conditions affect the risk. METHODS:Questionnaire data on hearing-related symptoms were analysed in women aged 24-65 (4718 preschool teachers, and 4122 randomly selected general population controls). Prevalence and risk ratio (RR) of self-reported hearing loss, tinnitus, difficulty perceiving speech, hyperacusis and sound-induced auditory fatigue were assessed by comparing the cohorts in relation to age and self-reported occupational noise and stressful working conditions (effort-reward imbalance and emotional demands). RR was calculated using log-binomial regression models adjusted for age, education, income, smoking, hearing protection, and leisure noise. Incidence rates and incidence rate ratios (IRR) were calculated for retrospectively reported onset of all symptoms except sound-induced auditory fatigue. RESULTS:Compared to the controls, preschool teachers had overall more than twofold RR of sound-induced auditory fatigue (RR 2.4, 95% confidence interval 2.2-2.5) and hyperacusis (RR 2.3, 2.1-2.5) and almost twofold for difficulty perceiving speech (RR 1.9, 1.7-2.0). Preschool teachers had a threefold IRR of hyperacusis (IRR 3.1, 2.8-3.4) and twofold for difficulty perceiving speech (IRR 2.4, 2.2-2.6). Significantly although slightly less increased RR and IRR were observed for hearing loss and tinnitus. RR and IRR were generally still increased for preschool teachers when stratified by age and occupational exposure to noise and stress. CONCLUSIONS:This large cohort study showed that working as preschool teacher increases the risk of self-reported hearing-related symptoms, indicating a need of preventative measures.

Early-age exposure to noise may have long-term health implications of which we have little knowledge of today. Age-specific hearing, learning inadequate coping strategies, and alterations in biological stress regulatory responses could play a role in the long-term health impacts. In Sweden about half a million children in the age between 1-5 years attend preschool. The noise exposure at preschools is intermittent and unpredictable and levels reach up to 84 dB LAeq (time indoors) with maximum levels of 118 dB LAF, mostly due to child activity. To increase the overall understanding of the possible implications of preschool noise environments for children, this paper describes children's behavioral and emotional reactions to and coping with their everyday sound environment from a teachers perspective. A postal questionnaire study performed in 2013-2014 with answers from 3,986 preschool teachers provided the data. Content analysis was combined with quantitative analysis. Eighty-two percent of the personnel considered that children's behavior was affected rather or very much by preschool noise. The most prevalent behaviors were categorized into: be heard, be distracted, show negative internal emotions, crowd, avoid, withdraw, be exhausted, and learning. The quantitative analyses confirmed an association between the perceived loudness and noise annoyance at preschool and affirmative reporting on noise affecting the children´s behavior. Age of the personnel, with the youngest age group reporting noise related behavior less often, and age distribution of the class, with 1-5 years old seeming less affected by noise, were also indicated, while pedagogic orientation was not a significant factor. Future studies should address the long-term health effects of these behaviors.

Objective: To validate self-reported hearing-related symptoms among personnel exposed to moderately high occupational noise levels at an obstetrics clinic. Design: Sensitivity, specificity, and predictive values were calculated for questionnaire items assessing hearing loss, tinnitus, sound sensitivity, poor hearing, difficulty perceiving speech, and sound-induced auditory fatigue. Hearing disorder was diagnosed by pure-tone audiometry, distortion product otoacoustic emissions, and HINT (Hearing In Noise Test). Study sample: Fifty-five female obstetrics personnel aged 22-63 participated; including 26 subjects reporting hearing loss, poor hearing, tinnitus, or sound sensitivity, and 29 randomly selected subjects who did not report these symptoms. Results: The questionnaire item assessing sound-induced auditory fatigue had the best combination of sensitivity85% (95% CIs 56 to 100%) and specificity70% (95% CIs 55 to 84%) for hearing disorder diagnosed by audiometry or otoacoustic emission. Of those reporting sound-induced auditory fatigue 71% were predicted to have disorder diagnosed by otoacoustic emission. Participants reporting any hearing-related symptom had slightly worse measured hearing. Conclusions: We suggest including sound-induced auditory fatigue in questionnaires for identification of hearing disorder among healthcare personnel, though larger studies are warranted for precise estimates of diagnostic performance. Also, more specific and accurate hearing tests are needed to diagnose mild hearing disorder.

Noise-induced hearing disorder has been thoroughly studied among workers in industry-like settings, but less so in female-dominated occupations. In Sweden, noise-related occupational disease among women are reported most frequently in the education sector. We analysed questionnaires from 4,932 women with preschool teacher’s degree who have worked in preschool compared to 5,065 randomly selected women without preschool work-history (response rate 51% vs. 38%). The age range was 24–71 in both cohorts (mean 46 [SD 11] among preschool teachers and 51 [11] among controls). Prevalence and prevalence ratio in age-strata and Mantel-Haenszel pooled risk were calculated for hearing-related symptoms. Noise exposure was compared between the cohorts. A 5% level of significance was applied. Occupational noise exposure and noise annoyance were significantly more common among teachers than controls: 75% vs.31% and 69% vs.26%, respectively. Still, significantly fewer teachers used hearing protection: 3% vs. 4%. Prevalence of hearing-related symptoms was much higher among teachers than controls: sound-induced auditory fatigue (71% [95% CI: 70–72] vs. 31% [30–32]), difficulty perceiving speech (46% [45–47] vs. 26% [25–27] and hyperacusis (38% [37–39] vs. 18% [17–19] and slightly higher for hearing loss (19% [18–20] vs. 17% [6–18] and tinnitus (19% [18–20] vs. 15% [14–16]. Teachers had a twofold risk of sound-induced auditory fatigue (PR-MH 2.2 [95% CI: 2.1–2.3] and hyperacusis (PR-MH 2.1 [1.9–2.2] compared to controls, when adjusted for age. The risk was also increased for difficulty perceiving speech (PR-MH 1.8 [1.7–1.9], tinnitus (PR-MH 1.4 [1.3–1.6] and hearing loss (PR-MH 1.4 [1.3–1.5]. Mean age of onset was significantly lower among teachers for all symptoms, except for hyperacusis (p = 0.902). Leisure-noise was significantly more common among controls. Family history of hearing loss did not differ (p = 0.411). The study is the first to show that preschool teachers have an increased risk of hearing-related symptoms, which may be caused by the work environment.

Background Perception of speech is crucial in school where speech is the main mode of communication. The aim of the study was to evaluate whether a web based approach including listening tests and questionnaires could be used as a screening tool for poor classroom acoustics. The prime focus was the relation between pupils’ comprehension of speech, the classroom acoustics and their description of the acoustic qualities of the classroom. Methodology/Principal Findings In total, 1106 pupils aged 13-19, from 59 classes and 38 schools in Sweden participated in a listening study using Hagerman’s sentences administered via Internet. Four listening conditions were applied: high and low background noise level and positions close and far away from the loudspeaker. The pupils described the acoustic quality of the classroom and teachers provided information on the physical features of the classroom using questionnaires. Conclusions/Significance In 69% of the classes, at least three pupils described the sound environment as adverse and in 88% of the classes one or more pupil reported often having difficulties concentrating due to noise. The pupils’ comprehension of speech was strongly influenced by the background noise level (p<0.001) and distance to the loudspeakers (p<0.001). Of the physical classroom features, presence of suspended acoustic panels (p<0.05) and length of the classroom (p<0.01) predicted speech comprehension. Of the pupils’ descriptions of acoustic qualities, clattery significantly (p<0.05) predicted speech comprehension. Clattery was furthermore associated to difficulties understanding each other, while the description noisy was associated to concentration difficulties. The majority of classrooms do not seem to have an optimal sound environment. The pupil’s descriptions of acoustic qualities and listening tests can be one way of predicting sound conditions in the classroom.

ObjectiveThere is a lack of research on effects of occupational noise exposure in traditionally female-dominated workplaces. Therefore, the aim of this study was to assess risk of noise-induced hearing-related symptoms among obstetrics personnel.DesignA cross-sectional study was performed at an obstetric ward in Sweden including a questionnaire among all employees and sound level measurements in 61 work shifts at the same ward.Participants115 female employees responded to a questionnaire (72% of all 160 employees invited).Main outcome measuresSelf-reported hearing-related symptoms in relation to calculated occupational noise exposure dose and measured sound levels.ResultsSound levels exceeded the 80 dB LAeq limit for protection of hearing in 46% of the measured work shifts. One or more hearing-related symptoms were reported by 55% of the personnel. In logistic regression models, a significant association was found between occupational noise exposure dose and tinnitus (OR=1.04, 95% CI 1.00 to 1.09) and sound-induced auditory fatigue (OR=1.04, 95% CI 1.00 to 1.07). Work-related stress and noise annoyance at work were reported by almost half of the personnel. Sound-induced auditory fatigue was associated with work-related stress and noise annoyance at work, although stress slightly missed significance in a multivariable model. No significant interactions were found.ConclusionsThis study presents new results showing that obstetrics personnel are at risk of noise-induced hearing-related symptoms. Current exposure levels at the workplace are high and occupational noise exposure dose has significant effects on tinnitus and sound-induced auditory fatigue among the personnel. These results indicate that preventative action regarding noise exposure is required in obstetrics care and that risk assessments may be needed in previously unstudied non-industrial communication-intense sound environments.

Exposure to high sound pressure levels is well known to cause auditory damage, regardless of age. There is however limited knowledge of the effects on hearing due to noise exposure early in life. In addition, no well-established model is used to describe how children perceive and experience their sound environment compared to adults. New studies of children’s hearing have revealed different directivity pattern especially at high frequencies given by the head-related transfer functions due to the anthropometric data of the children and also an ear canal resonance at considerable higher frequencies compared to adults. Recent studies also describe children feeling a great deal of discomfort when exposed to sounds with high frequency characteristics. Children today are exposed to high sound levels from an early age at preschool, school and during leisure time. Few studies have looked at general health effects or hearing in particular. It is being discussed whether age related hearing loss, regarded as an inevitable part of life, to a large extent may be caused by a lifetime of noise exposure starting early in life. This paper will review available studies on noise induced hearing damage among children and give suggestions for future studies within this field.

Noise-induced hearing disorder is under reported in female-dominated occupations, hindering knowledge on associated risk factors. We performed a cross-sectional study in Sweden, including 4,718 female preschool teachers and 4,122 randomly selected women age 24-65. In hypothesised causal models, we explored the effect of occupational noise exposure (e.g. self-reported retrospective and current exposure, hearing protection) on hearing-related symptoms (hearing loss, speech perception, tinnitus, hyperacusis, soundinduced auditory fatigue). Noise annoyance, job-stress and stress response were assessed for mediating and modifying effects. Exposure to occupational noise significantly increased the risk of hearing-related symptoms among preschool teachers (RRs 1.19-1.42 in adjusted log-binomial regression models). Consistent with our hypothesis, annoyance mediated the effect of noise exposure on soundinduced auditory fatigue (indirect effect β=0.28). In contrast, annoyance modified the effect of noise exposure on both hyperacusis and speech perception. For sound-induced auditory fatigue and hyperacusis, job-stress exposure and stress response both modified the effect and significantly interacted with noise exposure. The models provide better understanding of possible mechanisms for developing hearing-related symptoms. These findings will be further explored using longitudinal design.